| 摘要 |
The invention pertains to a process for producing free-floating luminous letters or two- or three-dimensional images. To do this, laser beams whose emission frequency lies preferably outside the visible spectral range are focussed on places where the bright image points are to be produced, thereby generating in the atmosphere light flashes caused, for example, by field ionization of the air molecules and subsequent recombination. The focal point of the laser beams is progressively shifted in lines and columns, thereby composing from individual light flashes an image that is repeated so as to produce a stationary image with an image frequency above 16 Hz. |
